When large numbers of people congregate at entertainment events or public transportation facilities, detecting exposure to possibly hazardous or otherwise unknown substances presents important real-time security and safety challenges. Infected patients in healthcare facilities present similar challenges of identifying possibly hazardous or contagious substances. A monitor that can detect and identify an unknown, possibly hazardous or contagious, substance would be beneficial, especially in the aforementioned environments.
Conventional monitors require labeling a reagent for each chemical of interest, for instance, via fluorescence. The conventional monitors are generally based on gas chromatography, ion mobility spectroscopy and Raman spectroscopy, which are bulky and power hungry instruments. An alternative, label-free approach includes analyzing a unique absorption spectrum of each substance of interest in a mid-infrared region. The mid-infrared spectroscopy enables simultaneous identification and quantification of a plurality of substances, even in the presence of interferences. At present, however, the mid-infrared spectroscopy requires bench-top optical instruments (e.g., Fourier transform infrared spectroscopy), which are substantial in size and unsuitable for wearable monitors.
Current designs generally lead to monitors with high power demand that are not wearable and/or mobile for in-situ substance (e.g., chemical and gas) detection. Accordingly, what is needed in the art is an improved monitor that can detect hazardous substances in real time that overcomes deficiencies of the prior art.